killpg.c\signal\src - musl - musl - an implementation of the standard library for Linux-based systems

#include <signal.h>
#include <errno.h>
int killpg(pid_t pgid, int sig)
{
	if (pgid < 0) {
		errno = EINVAL;
		return -1;
	}
	return kill(-pgid, sig);
}